Nitrated TATB is an insensitive energetic material used in various military applications. TATB is used in warhead fuzes and also as the explosive component in insensitive high explosives, such as in plastic bonded explosive compositions. TATB has been produced from various starting materials, such as 1,3,5-trichlorobenzene, 3,5-dichloroanisole, trinitrobenzene, picramide, or phloroglucinol, which is also known as 1,3,5-trihydroxybenzene. While various methods of producing TATB are known, TATB is not currently available from a qualified supplier for Department of Defense applications.
TATB has been synthesized via a multistep synthesis from 1,3,5-trichlorobenzene (“TCB”) using a process that generates environmentally problematic organic and salt waste streams.
Another method of synthesizing TATB from phloroglucinol is described in GB 2355715. The phloroglucinol is nitrated using sodium nitrite and nitric acid, forming trinitrophloroglucinol (“TNPG”), which is also known as 1,3,5-trihydroxy-2,4,6-trinitrobenzene. The nitric acid is added sequentially or in multiple additions. When cooled, a solid is produced, which is filtered, washed with 3M hydrochloric acid (“HCl”), and dried, yielding a solid product that is a monohydrate of TNPG. The monohydrate of TNPG is a free-flowing solid. The TNPG is alkoxylated using a trialkyl orthoformate, such as triethyl orthoformate (“TEOF”), forming 1,3,5-triethoxy-2,4,6-trinitrobenzene (“TETNB”). The alkoxylation of TNPG requires a ninefold molar excess of triethyl orthoformate, producing a waste stream of ethyl formate, ethanol, and diethyl ether. The ethanol and ethyl formate are removed by distillation. The solution of TETNB is concentrated, yielding TETNB as a solid, which is recrystallized from ethanol. The purified TETNB is aminated using liquid ammonia, filtered, washed with N-methylpyrrolidinone and methanol, and dried, yielding crystals of the TATB. The TATB synthesis utilizes multiple drying and isolation acts to produce solid products of TNPG, TETNB, and TATB.
Since intermediates formed during the TATB synthesis are sensitive to impact, friction, or electrostatic discharge (“ESD”), or are otherwise dangerous to handle, it would be desirable to minimize exposure of personnel and equipment to the intermediates. In addition, it would be desirable to reduce the amount of labor and time needed to produce the TATB and to improve the purity of the TATB and TETNB.